package com.ruoyi.websocket;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.Queue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;

/**
 * WebSocket的具体实现类
 *
 * @author wgb
 * @date 2024/06/06
 */
@ServerEndpoint("/websocket/{userId}")
@Component
@Slf4j
public class WebSocketServer {

    /**静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。*/
    private static int onlineCount = 0;
    /**concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。*/
    private static ConcurrentHashMap<String,WebSocketServer> webSocketMap = new ConcurrentHashMap<>();

    private static ConcurrentHashMap<String, Queue<String>> offlineMessages= new ConcurrentHashMap<>();

    /**与某个客户端的连接会话，需要通过它来给客户端发送数据*/
    private Session session;
    /**接收userId*/
    private String userId="";


    /**
     * 连接建立成功调用的方法*/
    @OnOpen
    public void onOpen(Session session, @PathParam("userId") String userId) throws IOException {
        this.session = session;
        this.userId=userId;
        if(webSocketMap.containsKey(userId)){
            webSocketMap.remove(userId);
            webSocketMap.put(userId,this);
            //加入set中
        }else{
            webSocketMap.put(userId,this);
            //加入set中
            addOnlineCount();
            //在线数加1
        }

        Queue<String> messages = offlineMessages.get(userId);
        if (messages != null) {
            while (!messages.isEmpty()) {
                sendInfo(messages.poll(), userId);
            }
            offlineMessages.remove(userId);
        }

        log.info("用户连接:"+userId+",当前在线人数为:" + getOnlineCount());

        try {
            sendMessage("连接成功");
        } catch (IOException e) {
            log.error("用户:"+userId+",网络异常!!!!!!");
        }
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {

        if(webSocketMap.containsKey(userId)){
            webSocketMap.remove(userId);
            //从set中删除
            subOnlineCount();
        }
        log.info("用户退出:"+userId+",当前在线人数为:" + getOnlineCount());
    }

    /**
     * 收到客户端消息后调用的方法
     *
     * @param message 客户端发送过来的消息*/
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("用户消息:"+userId+",报文:"+message);
        //可以群发消息
        //消息保存到数据库、redis
    }

    /**
     *
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("用户错误:"+this.userId+",原因:"+error.getMessage());
    }

    /**
     * 实现服务器主动推送
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }

    public static void cacheOfflineMessage(String userId, String message) {
        offlineMessages.computeIfAbsent(userId, k -> new ConcurrentLinkedQueue<>()).offer(message);
    }


    /**
     * 实现服务器主动推送
     */
    public void sendAllMessage(String message) throws IOException {
        ConcurrentHashMap.KeySetView<String, WebSocketServer> userIds = webSocketMap.keySet();
        for (String userId : userIds) {
            WebSocketServer webSocketServer = webSocketMap.get(userId);
            webSocketServer.session.getBasicRemote().sendText(message);
        }
    }

    /**
     * 发送自定义消息
     * */
    public static void sendInfo(String message,@PathParam("userId") String userId) throws IOException {
        log.info("发送消息到:"+userId+"，报文:"+message);
        if(StringUtils.isNotBlank(userId)&&webSocketMap.containsKey(userId)){
            webSocketMap.get(userId).sendMessage(message);
        }else{
            cacheOfflineMessage(userId, message);
            log.error("用户"+userId+",不在线！");
        }
    }

    public static synchronized int getOnlineCount() {
        return onlineCount;
    }

    public static synchronized void addOnlineCount() {
        WebSocketServer.onlineCount++;
    }

    public static synchronized void subOnlineCount() {
        WebSocketServer.onlineCount--;
    }
}